There is an abundance of outstanding prospects, including a late big-time addition, will be in attendance at the Southern Cal Rivals.com Showcase Powered by FBU Select, which will be held from 1-6 p.m. Saturday at Oaks Christian in Westlake Village.

Here are four storylines heading into the event.

Mathis out to prove himself

Joe Mathis has already accepted his invitation to the U.S. Army All-American Bowl and he's one of the top prospects in the 2013 class but the four-star defensive end from Upland, Calif., wants an even higher ranking and to prove he might be a five-star recruit.

That's why, at the last minute, Mathis decided to attend this weekend's event and he's going to challenge a quality group of offensive linemen.

Mathis, who has more than 40 offers, is ranked as the sixth-best strongside defensive end and No. 71 prospect in the 2013 class. Another strong performance this weekend could move him up even more in the next round of rankings.

Offensive line group is strong

One of the best groups at the Rivals.com SoCal Showcase is at offensive line, where UCLA commit Sean Dowling, three-star Sean Harlow, who could make a move up soon, 2015 prospect Reno Rosene, who already has a Notre Dame offer, and others lead the way.

Williams has accepted his invite to the Rivals.com Five-Star Challenge in Atlanta this summer. Ware is loading up on offers, and Cobb and Dorton have a healthy list as well. Greene is a lefty playmaker who could start landing offers at any time.

One of the best things about this Rivals/FBU camp is that many top 2014 and 2015 skill position prospects are expected to compete and make a name for themselves. They'll definitely have their chances and it could be especially interesting to watch to see who emerges.

Note: It is not too late to register for this event. If you have received an invitation but have not registered yet, FBU is accepting walk-ups at registration, which starts at 1 p.m. for prospects who have already received their invite.